In the field of drive systems, a slew drive is a device that can safely hold radial and axial loads, as well as transmit a torque for rotation. A slew drive employs a worm mechanism, also called a screw drive, to turn a gear about an axis perpendicular to the axis of the worm. This combination reduces the speed of the driven member and also multiplies its torque. There are many applications for the slew drive. Currently, they are employed in the generation of renewable energy, particularly in solar and wind energy. Due to the load-holding power and rotational torque strength of slew drives, they are well suited to solar trackers and wind turbines. They can, however, be employed in substantially any instance where rotational movement, or “slewing” is desired.
While the current slew drives function quite well in performing the desired tasks, they can be difficult to attach to the structure to be rotated, can be heavy and can also be costly. Attaching a slew drive to structures to be rotated usually requires the fabrication of fittings to couple structures to the drive. Also, as the slew drive is increased in size to meet various uses, the weight can become increasingly problematic since as the worm and the driven gear are increased in size, the weight of material can rise quickly. In the industries in which slew drives are primarily used, less weight allows for quicker an easier installation of the drive, and less weight also allows for less manpower and additional cost savings.
Additionally, the cost of a slew drive often depends on the accuracy of rotation of the drive. A high accuracy is accomplished during fabrication of the driven gear. The tolerances achieved when machining or otherwise creating the teeth of the gear can greatly add to the cost of the slew drive, depending on the accuracy desired. This accuracy can be compromised during assembly of the slew drive gearbox. Bearings are tempered, and other heat treatments, are often required during assembly. These fluctuations in temperature can distort and reduce the accuracy of the driven gear. Thus, to maintain accuracy, the driven gear is often refinished to restore tolerances and eliminate distortions. Often, these tolerances cannot be completely restored to the original. This further adds to the cost of the drive. Accuracy is also reduced by the normal wear over time, on the driven gear as it is used.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
An object of the present invention is to provide a new and improved slew drive.
Another object of the present invention is to provide a slew drive that has reduced weight.
Yet another object of the present invention is to provide a slew drive with increased accuracy.
And another object of the present invention is to provide a slew drive with a replaceable driven gear segment.
And yet another object of the present invention is to make the installation of a slew drive easier.